A common signal indicator lamp is a cylindrical body, and can radiate light across the entire region in its circumferential direction.
In a light indicator device proposed in the following Patent Literature 1 as an example of the signal indicator lamp, a light-emitting diode substrate and a case that stores the substrate are included. On the substrate, a plurality of light source portions made up of LEDs are disposed. The case includes a base portion in a circular cylindrical shape with a bottom and three covers having translucency and showing circular cylindrical shapes. These covers are connected in three stages stacked with respect to the base portion. Each cover has a ring-shaped top wall at the inner peripheral side, and the top wall has a pair of bulging portions facing each other. At mutually opposite distal end portions in the pair of bulging portions, slits are defined. The substrate stored in the case is, inside of each cover, fitted in the respective slits of the pair of bulging portions. Light emitted from each light source portion of the substrate passes through the cover around the light source portion to be sent out to the outside.